EDIBLE OIL T2 PROFILES PROVIDE INSIGHTS INTO HUMAN ADIPOSE TISSUE FLUIDITY

Therapeutic Area

Novel Biomarkers

Background

Dietary fatty acid profiles have been linked to cardiovascular risk. The fatty acid profile of human adipose tissue (AT) mirrors dietary intake and hepatic de novo lipogenesis. In turn, lipogenesis is amplified by insulin resistance, another risk factor for cardiovascular disease. Thus, AT fluidity is a potential biomarker of cardiometabolic health and disease risk. To assess the fluidity and fatty acid composition of human AT non-invasively, our laboratory developed a patented device that measures the transverse relaxation times (T₂) of the human fingertip. Hypothesis: Biologically relevant edible oils of varying fatty acid composition show a linear association between T₂ and triacylglycerol (TAG) fluidity.

Methods

Lipid ¹H T₂ relaxation decay curves for edible oil samples were recorded at 37°C using a 0.47T Bruker mq20 benchtop magnetic resonance relaxometer operating at 20 MHz. The decay curves were deconvoluted into 3-component T₂ profiles using a discrete inverse Laplace transform (XPFit, Alango Ltd.). Macroscopic fluidity (1/viscosity) was measured at 37°C using a ViscoLab 5000 viscometer.

Results

Each T₂ profile contained 3 peaks assigned to distinct mobility domains within each TAG molecule. For Peak 1, the mean T₂ values in msec increased with cis-double content: 275.3 (olive oil, high oleic acid), 373.2 (safflower oil, high linoleic), 388.0 (cod liver oil, mixed composition), 459.7 (flaxseed oil, high alpha-linolenic), 488.6 (fish oil 2, moderate eicosapentaenoic, EPA, and docosahexaenoic, DHA) and 691.5 (fish oil 3, high EPA and DHA). Across this series of edible oils, the T₂ values were linearly associated with fluidity (R²= 0.83) and the average number of cis-double bonds per TAG molecule (R²= 0.95), p<0.001 (Figure 1). Similar linear associations were observed for Peaks 2 and 3.

Conclusions

The fluidity and cis-double bond content of biologically relevant TAGs can be monitored non-invasively using benchtop magnetic resonance. These results provide a framework for interpreting non-invasive adipose tissue T₂ measurements in the living human finger.